CVE-2009-3279 in Ts-239 Pro Turbo Nas
Summary
by MITRE
The QNAP TS-239 Pro and TS-639 Pro with firmware 2.1.7 0613, 3.1.0 0627, and 3.1.1 0815 create a LUKS partition by using the AES-256 cipher in plain CBC mode, which allows local users to obtain sensitive information via a watermark attack.
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Analysis
by VulDB Data Team • 06/12/2017
The vulnerability identified as CVE-2009-3279 affects QNAP TS-239 Pro and TS-639 Pro network-attached storage devices running specific firmware versions. This issue stems from the implementation of full-disk encryption using LUKS (Linux Unified Key Setup) with a cryptographic configuration that introduces significant security weaknesses. The affected devices utilize the AES-256 cipher algorithm but implement it in plain CBC (Cipher Block Chaining) mode without proper authentication or integrity protection mechanisms.
The technical flaw lies in the cryptographic implementation where the LUKS encryption system is configured to use AES-256 in plain CBC mode rather than authenticated encryption modes such as GCM or CCM. This configuration creates a vulnerability that allows local attackers to exploit what is known as a watermark attack. The watermark attack technique specifically targets the predictable patterns that emerge when CBC mode is used without proper integrity checking or authentication. In CBC mode, identical plaintext blocks produce identical ciphertext blocks, creating discernible patterns that can be analyzed to infer sensitive information about the encrypted data.
The operational impact of this vulnerability is significant for users of these QNAP devices as it compromises the confidentiality assurances provided by the full-disk encryption feature. Local users who have access to the system can potentially recover sensitive information from the encrypted partitions, undermining the fundamental security objective of disk encryption. The vulnerability affects the integrity of the encryption implementation and could allow attackers to reconstruct portions of the original data, particularly when dealing with predictable or repetitive data patterns. This weakness particularly impacts the security of stored data on network-attached storage devices where local access might be obtained through legitimate administrative activities or compromised user accounts.
The security implications extend beyond simple data recovery as this vulnerability demonstrates poor cryptographic implementation practices that violate established security standards. According to CWE-327, the use of weak or broken cryptographic algorithms and modes of operation represents a significant security risk. The configuration essentially creates a cryptographic primitive that is vulnerable to known attacks that exploit the deterministic nature of CBC mode. From an ATT&CK framework perspective, this vulnerability could be leveraged by adversaries during the privilege escalation and persistence phases, allowing them to access sensitive data that should remain protected by encryption.
Mitigation strategies for this vulnerability involve immediate firmware updates from QNAP to address the cryptographic implementation flaws. Organizations should also consider implementing additional access controls and monitoring to detect unauthorized local access attempts. The recommended approach includes upgrading to firmware versions that properly implement authenticated encryption modes and ensuring that all encryption implementations follow established cryptographic best practices. System administrators should also conduct thorough security assessments to identify any other potential cryptographic weaknesses in their storage infrastructure and consider alternative encryption approaches that provide both confidentiality and integrity protection.